1. Field of the Invention
The present invention relates to an apparatus and a method for simultaneously measuring velocity and an instantaneous spatial position of a spherical object.
2. Description of the Related Art
In a conventional method, flying velocity and a passing position of a spherical object such as a golf ball or a tennis ball are measured by using groups of sensors arranged at definite intervals along the flying direction of the ball and allowing the ball to intercept light of a plurality of ray projecting and receiving systems of the groups of sensors. The interval between the time when the spherical object begins to intercept light of a ray projecting and receiving system of a group of sensors and the time when the spherical object begins to intercept light of a ray projecting and receiving system of another group of sensors is measured, and the velocity of the spherical object is obtained from the time interval and the distance between the ray projecting and receiving systems, and the passing position of the spherical object is obtained from the position of the first ray projecting and receiving system intercepted by the spherical object.
In the conventional method, as shown in FIG. 6, part of the spherical object 102 protrudes beyond the base line 103 of a group of sensors 100 when a sensor 101 of the group of sensors 100 is intercepted, and part of the spherical object 102 protrudes beyond the base line 105 of another group of sensors 104 when a sensor 101 of the group of sensors 104 is intercepted.
In other words, if the distance the spherical object 102 protrudes beyond the base line 103 of the group of sensors 100 is defined as A.sub.1, the distance the spherical object 102 protrudes beyond the base line 105 of the group of sensors 104 is defined as B.sub.1, and the interval from the time a sensor 101 of the group of sensors 100 is intercepted to the time a sensor 101 of the group of sensors 104 is intercepted is defined as T, the spherical object 102 practically moved for L-A.sub.1 +B.sub.1 in T seconds. L is the distance between the groups of sensors 100 and 104.
In the foregoing conventional method, the velocity and position of the spherical object 102 are calculated on the basis of the distance L for which the spherical object 102 is supposed to have moved instead of the distance the spherical object 102 practically moved, therefore the velocity and position obtained by using the conventional method are not accurate.
It is therefore an object of the present invention to provide an apparatus and a method for measuring velocity and an instantaneous spatial position of a spherical object simultaneously, in which velocity and a position of a moving (including flying) spherical object are measured with high accuracy.